If you read the article , you will see that mr Bjork examines also other possibilities

" In order to accomodate the criticism.."

Including faster probes

"All though I have used a relativly high probe velocity of 0.1c, it is a possibility that even faster probes could be invented and thus decreasing the exploration time significantly"

but it conludes

"Returning now to the result obtained in this paper, i see, to be able to conclude based on the results from my simulation that exploring the galaxi by sending out probes to visit the other stars is horribly slow.However unless travel methods are invented which give access to faster-than_light travel,there seem to be no alternative way to proceed than this proposed process.This could offer a possible explanation to the Fermi paradox."

You must not be a genius to argue :

" wow... if you increase the speed..."
" ohhh , why dont you use more probes.."
" Hey guy, if you ..."

Mr Bjork has taken into account even exotic possibilities such as the use of self replicating probes
Nevertheless the exploration time remains ...horribly slow

Which should have led him to the conclusion that 'physically' searching by traveling through the universe is not the solution to having a good change of finding life?

Unless we figure out a fundamentally different way of space travel there's no way we will ever be able to search everywhere within an acceptable time-frame. As exotic as it might be, I think self replicating probes, as in exponentially increasing numbers of probes would still be the best way of searching when you're considering using not-so-sci-fi methods of propulsion and so on.

I thought there was no reason for you to continue, Alberto? Hehehe....

Very well then...



Well if he did, it's not in his most current paper upon which I am basing my analysis.

I find that he "mentions" the possibility of VNM and directed searches in his paper affecting his results, yet I find no evidence that the simulation he ran took these into account.

Hence, these factors are not taken into account in the Bjork simulation even if it is mentioned in the paper.

And thus our point, to once again to beat a dead horse, that Mr. Bjork has made a wildly speculative claim (Alien visitation is impossible) based on a very limited simulation (limited speed, limited probes, limited search pattern).



C remains the universal speed limit... that is still physically true. But to go from "horribly slow" to "visitation is impossible" is a wildly speculative leap with very little hard evidence or simulation evidence to back it up.



Well even if I was a genius I would still argue since the flaws are so obvious...

Nope,
you would still argue ( no doubt about it ) because you wont never admit to be wrong

Do you want to increase the speed from 0.1c up to 1.c ?
Do you think it is a smart solution ?

No it is not, for at least a couple of good reasons

a)
Did you notice that " Horribly slow " stands for " 3\4 the age of universe " ?

If some one claims
" it is impossible to go on foot, from New York to los Angeles , in one day "
and some one else replied
" On foot maybe not, but cycling it could be possible, it is ten time faster "

What would you think of him ?

b)
You give for granted that a further increase of the speed or in general of the technological level is, in any case , a benefit
Are you so sure ?

You must match the exploration time and the maximum amount of time at disposal for the exploration

this one is given by :

The age of their planet ( not of universe ) - The evolution time from the scratch up to the technological level

The higher the technological level the higher the needed time

Experience demostrate that it relativly easy to make big progress at the beginning but afterward the learning curve get steeper

In conclusion it may be not worth while waiting for a 1c technology simply becauste it would take too long time

Same consideration for self replicating probes

The only real advantage is to increase the number of probes
Mr Bjork run an other simulation with 200 probes and 8 sub probes
The result are quoted in the article

Nope,
you would still argue ( no doubt about it ) because you wont never admit to be wrong

Do you want to increase the speed from 0.1c up to 1.c ?
Do you think it is a smart idea ?
Are the flaws so obviuos ?

No it is not a smart idea and the flaws are obvious only for you, not for me
There are at least a couple of good reasons

a)
Did you notice that " Horribly slow " stands for " 3\4 the age of universe " ?

If some one claims
" it is impossible to go on foot, from New York to los Angeles , in one day "
and some one else argue
" On foot maybe not, but cycling it could be possible, it is ten time faster, why dont you give it a try ? "

What would you think of him ?

b)
You give for granted that a further increase of the speed or in general of the technological level is, in any case , a benefit
Are you so sure ?

You must match the exploration time and the maximum amount of time at disposal for the exploration

given by

The age of their planet - The evolution time from the scratch up to the technological level

The higher the technological level the higher the evolution time ,the shorter the time at disposal for organizing the exploration

Experience demostrate that it relativly easy to make progress at the beginning but afterward the learning curve get steep and steep

It may be not worth while waiting for the highest technological level


The only real advantage is to increase the number of probes
Mr Bjork run an other simulation with 200 probes and 8 sub probes
The result are quoted in the article

It would be silly to admit one is wrong until one is proven wrong... especially when you choose to work around my fundamental critique -- choosing .1c vs. .9c -- for the last three posts!




In terms of a simulation, from .1 c to .9 c, yes, I thought I made that clear.



Since it get's the probe to it's destination 9 times faster, then yes.



If you are limiting your probes to .1 c in your simulation, then yes.




All I said is that if you go faster, you reduce the search time, nothing more.



And came up with a search time of 1.5x10^7 vs. 10x10^9.

Which proves my point that the values for the parameters of the simulation are completely arbritray and there is nothing to stop us from changing those parameters to acheive whatever timescale we wish! Bjork wanted a large time scale so he cooked up his simulation for large scales; I want a small time scale so I can cook up his simulation for small scales. If the simulation were true, it would be irrelevant what we want but that is not the case here and that is my problem with drawing gradiose conclusions based on it.


Again, nothing in this paper is conclusive. It is a overly simple simulation that is based on many speculative assumptions. It does give insight however IF we go at .1 c and IF we limit ourselves to 200 probes and IF the we don't construct new probes. But we don't know that aliens (or ourselves) will limit themselves to any of these parameters.

This simulation is not the answer to Alien question. I'm sorry if you can't see that Alberto, but I've tried my best to point out the scientific flaws in Mr. Bjork's analysis. If you continue to believe him, then that is your personal perogative, but it won't hold water in any public discussion as we are having.

That's my problem with this whole theorizing of Bjork too.



Regardless of the total duration the search process would STILL take, you are aware that it's possible to cut the total duration in half just by doubling the speed? Combine this with a rather huge amount of self-replicating probes and it's suddenly not so impossible anymore, as each doubling could speed up the search process considerably.

Seems to me it's actually a pretty clever to increase the speed a lot if you want to be able to search faster.



I would think he has a better chance of winning his little bet there when he would suggest 2 hours and then take a flight with a Concorde instead....

Suggesting a method of transportation that is ten times faster is still a good suggestion in a relative sense, but it won't achieve their ultimate set goal. Does it therefore mean it's a stupid idea?? Heck no, you just need to increase the speed even more, ten times faster just isn't enough.

Everybody can tell the guy starting on foot going from New York to LA will be last, regardless of whether he walks it in under one hour (impossible, I know) or 10 months or 10 years.



Actually, considering the size of our universe all we really need is to get lucky in our search.

As numbers and math show, it's probably not entirely impossible to search the whole universe, but it would simply take too long with the methods suggested here making it 'practically impossible' I guess.

Also, Mr Bjork can't claim that it's literally impossible as he himself made the assumption starting with something like; unless we invent a much much faster method of propulsion, it's "impossible". So I don't think he meant theoretically impossible, but rather practically impossible? I don't know if he even makes this distinction though.



Also, the 200 probes seems like an incredibly small amount anyways, just imagine what would happen if you take 1 million probes to start with instead. I mean, we can mass produce billions of cellphones, so there's no reason to assume we couldn't mass produce something like those probes. I mean, assuming the technology for self-replication has been invented, it's not such a big step anymore anyways. (Off course speed will then be the bottleneck, but I figure it would still help, right?)

Here's another point on the probe issue. So far, we have discussed VNM, machines making machines. In fact, I think there has been an unstated assumption that the probes were unmanned.

However consider manned probes. Upon arriving at a new system, that probe and it's crew set about creating 10's, 100's, 1000's more probes from the raw material of the new system.

I bring this up because it allows for VNM-like expansion with current day technology and is thus could easily be modeled in Bjork v2.0




It's in his conclusion too:

"However,
unless travel methods are invented which gives access to
faster-than-light-travel, there seems to be no alternative
way to proceed than this proposed process."

Which again highlights my fundamental problem with the author making a wildly speculative claim (FTL seems the only choice for galactic exploration) based on a very limited simulation (200 .1 c probes).

It reminds me some previous threads with the creationists

Anytime the evolutionists prove how absurd their theories are, the common reply is " Ehhh but He is God..."
Of course, at this point you are in troubles, how can you reply at such comment ?

You quit and that's it

The point is that in case of religion such answer might even make some sense but applying the same techniques also to the aliens is simply ridicoulus

You need a longer time to achieve a more sophisticated technology ?
It doesnt' matter , they are Gods..pardon aliens , they can do everything in a short time

If you use 200 probes the exploration time is only : 15.000.000 years
Only my God...he said only 15 milion years?
Really he did ?
Please note 15 milion years just to explore 4 % of the galaxi
He his not talking about the whole galaxi, just a miserable 4 %
A non stop 15 milion years voyage ?
Of course narrow minded guy, they are alien probes

Why only 200 probes ?
1 milion same as the cellular telephones

I could argue that in these case the univers would be full of radiofrequencie..sorry sorry ..the aliens can comunicate without using elettromagnetic fields

An then use the self replicating probes
Why not ?
A star ship capable of building a copy of itself
A toy for the aliens

one probe has finally found our earth...hurrah...hurrahh
Well there is a small problem, it is 1000 light years far away from theit native planet
How can they reach us ?
( for your information the diameter of our galaxi is 100.000 light yeers, so as you can see they are pretty close to us)
As usual the lack of fantasy of this guy is apalling

They have invented the teletransport in a couple of weeks they reach our earth
But the max speed for teletransport is 1c they take 1000 years to go and 1000 years to get back
Of course it is an exotic teletransport
it is not the primitive teletransport that human beings will discover may be in 10.000 years from now
Even so ?
Do you think that a 1000 thousand years voyage is a problem for an alien ?
He read a good book


At this point I am really fed up

Why dont you E-mail Mr Bjork your remarks ?

I take the liberty to give you a suggestion

Phemox tell him you are an artist
fastlane69 dont tell him you are a scientist

I'm still here.




I don't know about others, but I have not used this line of arguement in any of my posts.

In fact, for the last 5 or 6 posts, I've only asked one fundamental, very physical, question:

"What effect does limiting the simulation to .1 c have on the conclusion?"

This "creationism" analogy is the latest in a long series of attempts to not answer this one, fundamental question.